Cancer Rate Research

Cancer Rate Research

Data from 2003 – 2014 and reported as age-adjusted incidence rates of childhood cancer per 1 million.

United States Average – 173.7

10 States with highest incidence:

  • New Hampshire – 205.5
  • New Jersey – 192. 3
  • Maine – 190.5
  • New York – 190
  • Pennsylvania – 186.6
  • Connecticut – 185.8
  • Nebraska – 183.2
  • Texas – 183.2
  • Oregon – 182.6
  • Massachusetts – 181.5

Siegel et al. Geographic Variation in Pediatric Cancer Incidence – US, 2003-2014. MMWR, 2018

Total Rate of Pediatric Cancer (CDC)

Incidence of pediatric cancer in Nebraska

Map of Nebraska counties with pediatric cancer rates above the state normal.
Map of Nebraska counties with pediatric brain tumor rates above the state normal.

(Farazi, et al. Cancer Epi, 2018)

Drinking Water Nitrate Effects and Human Health

There is currently a regulatory limit for nitrate in public drinking water supplies (10mg/L), however this was set to protect against methemoglobinemia in infants. Other health effects were not taking into account when setting the nitrate limit.

N-nitroso compounds are considered probable human carcinogens by the International Agency for Research on Cancer. A study evaluating thyroid cancer found that women who were exposed to nitrate in their drinking water with levels exceeding 5 mg/L were 2.6 times more likely to develop thyroid cancer. Women exposed to high rates of nitrate in drinking water were also found to be at increased risk of ovarian cancer. Overall, breast cancer risk was not associated with water nitrate levels. Study results on bladder and stomach cancer are mixed. 

There have been several studies looking into high concentrations of nitrate in drinking water and a correlation to colon cancer risk. A study in Wisconsin found an elevated risk for proximal colon cancer among women estimated to have high nitrate concentration in their drinking water but did not find a link to rectal cancer.

Adverse health effects due to ingestion of nitrate in drinking water are most likely the result of complex interactions and more research is needed to establish firm conclusions. 

Ward, Mary H et al. “Drinking Water Nitrate and Human Health: An Updated Review.” International journal of environmental research and public health vol. 15,7 1557. 23 Jul. 2018, doi:10.3390/ijerph15071557

Atrazine and nitrate in drinking water associated with higher risk of lymphoma

When atrazine and nitrate are present in an acidic environment, such as the human stomach, they can form a nitrosamine called NNAT(N-nitrosoatrazine). Many nitrosamines are carcinogenic and cause birth defects in animals.

In human lymphocytes, nitrosamines can cause changes to the chromosomes at doses 1000 times lower than that of nitrate or atrazine alone. Suggesting a mixture of both is more toxic than exposure to just one contaminant alone.

  • NHL (Non-Hodgkin Lymphoma) risk is 2.5 times higher for subjects exposed to nitrate and atrazine in drinking water compared to subjects not exposed.
  • Indolent B-cell lymphoma risk – 3.5 times higher for subjects exposed to nitrate and atrazine in drinking water compared to subjects not exposed.
  • Hypothesis:  Increased NHL risk due to in vivo formation of NNAT causing chromosomal mutations during metabolism leads to the development of cancer.

Rhoades et al “Atrazine and Nitrate in Public Drinking Water Supplies and Non-Hodgkin Lymphoma in Nebraska, USA” Environ Health Insights 2013; 7: 15-27

Counties with groundwater nitrate concentration between 2.1 and 5 mg/L have higher incidence of pediatric cancer.

63% (54/86) Pediatric CNS Cancers

Age-adjusted incidence (AAI) of pediatric brain and other CNS cancer per county in Nebraska from 1987-2016

41% (35/86) Pediatric Leukemia  

Age-adjusted incidence (AAI) of pediatric leukemia per county in Nebraska from 1987-2016

43% (38/86) Pediatric Lymphoma 

Age-adjusted incidence (AAI) of pediatric lymphoma per county in Nebraska from 1987-2016

These maps examine the cancer incident rate of the three major types of pediatric cancer in Nebraska counties. Counties that are white were not included in the study.

The study was conducted to examine the nitrate and atrazine groundwater concentrations in Nebraska and found that counties with groundwater nitrate concentrations between 2.1 and 5 mg/L had a higher incidence rate for pediatric brain cancer, other central nervous system cancers, leukemia, and lymphoma than those counties that tested for lower concentrations. The same was found for counties with atrazine concentrations between 0.95-2.82 μg/L.

“Geospatial Distribution of Age-adjusted Incidence of the Three Major Types of Pediatric Cancers and Waterborne Agrichemicals in Nebraska” Ouattara B., Puvvula J., Abadi A., Munde S., Kolok A., Bartel-Hunt S., Bell J., Wichman C., Rogan E. Earth and Space Science Open Archive (March 11, 2021)

Effects of Processed Meat and Drinking Water Nitrate on the Microbiome

Studies have linked processed meat consumption to increased colorectal cancer risk, but we don’t really know why. One suggestion is the production of carcinogenic N-nitroso compounds (NOCs) in the gastrointestinal tract. When oral and gut microbes ingest certain proteins they can generate NOCs.

The study found that drinking high nitrate water increases oral bacteria that can contribute to increased N-nitroso compounds that are considered carcinogenic. Meat nitrate/nitrite at the levels tested had little to no effect on gut or oral bacteria. 

Sinha R, Zhao N, Goedert JJ, Byrd DA, Wan Y, Hua X, Hullings AG, Knight R, Breda SV, Mathijs K, de Kok TM, Ward MH; PHYTOME consortium members. Effects of processed meat and drinking water nitrate on oral and fecal microbial populations in a controlled feeding study. Environ Res. 2021 Mar 27;197:111084. doi: 10.1016/j.envres.2021.111084. Epub ahead of print. PMID: 33785324.

Assessment of potential economic cost of nitrate-attributable cancer cases

Based on national nitrate occurrence data and relative risk ratios, its been estimated that there are 2,300 to 12,594 nitrate-attributable cancer cases. In particular the meta-analysis of eight studies found a positive association for nitrate exposure and colorectal cancer risk.

Through medical expenditures alone the burden of nitrate-associated cancer cases corresponds to an annual economic cost of 250 million to 1.5 billion dollars, together with a potential 1.3 to 6.5 billion dollar impact due to lost productivity.

Lowering exposure to nitrate in drinking water could bring economic benefits by lessening the impacts of nitrate-associated diseases.

“Exposure-based assessment and economic valuation of adverse birth outcomes and cancer risk due to nitrate in United States drinking water.”
Temkin A, Evans S, Manidis T, Campbell C, Naidenko O. Environmental Research Vol. 176 (Sept. 2019) 108442